Field of the Invention
The present invention relates to a liquefied petroleum gas (LPG) a liquefied petroleum gas (LPG) filling system of a bi-fuel vehicle. More particularly, it relates to an LPG filling system of a bi-fuel vehicle that is configured for reducing the temperature and pressure in an LPG bombe for storing LPG in the case in which the external temperature is very high, e.g. in the hot season, wherein it is possible to refill the LPG bombe with LPG.
Description of Related Art
A bi-fuel vehicle using both gasoline and LPG is separately equipped with a gasoline supply system including a gasoline tank and a liquefied petroleum gas (LPG) a liquefied petroleum gas (LPG) supply system including an LPG bombe.
As shown in FIG. 1, a process of filling the LPG bombe of the bi-fuel vehicle with LPG includes a step of operating a filling pump 2 of an LPG filling station, a step of supplying LPG from an LPG storage space 1 of the LPG filling station to a filling gun 3 as the result of operating the filling pump 2, and a step of filling the LPG bombe of the vehicle with LPG through the filling gun 3.
However, in the case in which the external temperature is very high, e.g. in the hot season, the pressure in the LPG bombe of the vehicle may be higher than the LPG filling pressure, with the result that LPG filling is not possible.
That is, in the case in which the pressure in the LPG bombe of the vehicle is higher than the LPG filling pressure, a check valve of an excess flow valve mounted in an LPG injection port of the bombe is not opened, with the result that it is not possible to fill the LPG bombe with LPG through the filling gun.
For example, when the atmospheric temperature in the hot season is approximately 40° C. or higher, the pressure in the LPG bombe of the vehicle becomes higher (e.g. 16.5 bar) than the LPG filling pressure in the filling gun (e.g. 16.3 bar=the pressure in the LPG storage space of the LPG filling station 8.3 bar+the LPG pumping pressure as the result of operating the filling pump 8.0 bar). Consequently, the check valve of the excess flow valve mounted in the LPG injection port of the bombe is not opened, with the result that it is not possible to fill the LPG bombe with LPG through the filling gun.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.